Make handling of sys/name dependend on config flag

[AleksanderWWW]

Before submitting checklist

• Did you update the CHANGELOG? (not for test updates, internal changes/refactors or CI/CD setup)
• Did you ask the docs owner to review all the user-facing changes?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 75.61%. Comparing base (b3311f4) to head (5eadb4f).

Additional details and impacted files

@@             Coverage Diff             @@
##           dev/1.x    #1777      +/-   ##
===========================================
- Coverage    81.21%   75.61%   -5.60%     
===========================================
  Files          304      304              
  Lines        15365    15365              
===========================================
- Hits         12478    11618     -860     
- Misses        2887     3747     +860     

Flag	Coverage Δ
e2e	?
e2e-management	?
e2e-s3	?
e2e-s3-gcs	?
e2e-standard	?
macos	75.28% <100.00%> (-5.65%)	⬇️
py3.10	?
py3.11	?
py3.12	?
py3.7	74.99% <100.00%> (-5.68%)	⬇️
py3.8	75.28% <100.00%> (-5.77%)	⬇️
py3.9	?
ubuntu	74.86% <100.00%> (-6.17%)	⬇️
unit	75.61% <100.00%> (-0.02%)	⬇️
windows	73.89% <100.00%> (-6.73%)	⬇️

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[AleksanderWWW]

Manual tests:

import neptune


with neptune.Run() as run:
    run.sync()
    print(run["sys/name"].fetch())

• Current app.neptune.ai - name is set automatically to Untitled ✅
• If the flag is present - name is None and is handled by the backend ✅

Neither of these scenarios raises an exception

[szysad]

LGTM